functional prototype

update docs and structs, add actual logic, now it actually works

docs/behind-the-scenes/commands.md

@@ -0,0 +1,3 @@
+# How commands are run
+
+I was unable to find a way to directly run *multiple* commands via Docker/Podman. Instead of doing that, greg puts all the commands in a temporary script, mounts it inside, and then run it with